1. Technical Field of the Invention
The present invention involves a device and a method used in the field of manufacturing reticles and masks which are manufactured using resist-coated substrates.
2. Background of The Prior Art
Electron beam lithography involves use of focused electron beams to expose radiation-sensitive resist materials. Such lithography is advantageous because electron beams can be readily scanned and accurately positioned on substrates.
Electron beam lithography can involve long exposure times (writing times) for producing reticles, the exposure times often being on the order of hours. The problem of long exposure times has become worse with the increasingly large size of reticles to be written, and with the increased desirability of small feature sizes, because smaller feature sizes require smaller electron beams.
One possible solution to the long writing times is to employ chemically amplified electron-sensitive resists. Such chemically amplified resists require less energy for exposure, thus reducing writing times. However, chemically amplified resists are prone to chemical instability after exposure. This chemical instability can be overcome by baking the resist after exposure. Presently, such baking is performed after all of the exposure of the resist has been accomplished. This may result in unacceptable delays between the writing and baking processes, especially in view of the trends noted above toward larger reticles and smaller feature sizes.
From the foregoing, it is seen that it would be advantageous to have improved methods for using electron beams to expose chemically amplified resists.
A device for exposing and heating a substrate coated with resist includes an exposure tool for selectively exposing the resist and a heater for heating the exposed resist. A method of patterning resist on the substrate includes selectively exposing resist on a first portion of a substrate, heating the exposed resist on the first portion of the substrate, and selectively exposing resist on a second portion of the substrate. According to a particular embodiment of the invention, the heating of the first portion and the exposing of the second portion may be performed simultaneously.
According to an aspect of the invention, a device for exposing and heating resist includes a sensor for detecting position of a grid which is on the resist or reticle. This allows correction of the selective exposure of the reticle to account for changes in the alignment between the reticle and an exposure tool. Such changes in alignment may be due, for example, to heating of portions of the resist.
According to another aspect of the invention a method of exposing and heating resist on a substrate includes compensating for changes in the position of the resist due to expansion of the substrate and/or the resist layer atop the substrate due to heating of the resist and/or the substrate.
According to yet another aspect of the invention, a device for exposing and heating a substrate coated with resist includes an electron beam generator and a laser light source operatively coupled to the electron beam generator.
According to a further aspect of the invention, a device for exposing and heating a substrate coated with resist includes an exposure tool for selectively exposing the resist and a heater for heating exposed resist, the heater operatively coupled to the exposure tool. The exposure tool simultaneously act on different portions of the resist.
According to a still further aspect of the invention, a method of patterning resist on a substrate includes the steps of 1) selectively exposing the resist on a first portion of the substrate; 2) heating the resist on the first portion; and 3) selectively exposing the resist on a second portion of the substrate.
To the accomplishment of the foregoing and related ends, the invention comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.